package com.smart.primary.util;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;

public class JsonUtil {
	
	
	/**
	 * listToTree
	 * <p>方法说明<p>
	 * 将JSONArray数组转为树状结构
	 * @param arr 需要转化的数据
	 * @param id 数据唯一的标识键值
	 * @param pid 父id唯一标识键值
	 * @param child 子节点键值
	 * @return JSONArray
	 */
	public static JSONArray treeJson(JSONArray arr,String id,String pid,String child){
	   JSONArray r = new JSONArray();
	   JSONObject hash = new JSONObject();
	   //将数组转为Object的形式，key为数组中的id
	   for(int i=0;i<arr.size();i++){
	      JSONObject json = (JSONObject) arr.get(i);
	      hash.put(json.getString(id), json);
	   }
	   //遍历结果集
	   for(int j=0;j<arr.size();j++){
	      //单条记录
	      JSONObject aVal = (JSONObject) arr.get(j);
	      //在hash中取出key为单条记录中pid的值
	      JSONObject hashVP = (JSONObject) hash.get(aVal.get(pid).toString());
	      //如果记录的pid存在，则说明它有父节点，将她添加到孩子节点的集合中
	      if(hashVP!=null){
	         //检查是否有child属性
	         if(hashVP.get(child)!=null){
	            hashVP.put(child, aVal);
	         } else{
	            JSONArray ch = new JSONArray();
	            ch.add(aVal);
	            hashVP.put(child, ch);
	         }
	      }else{
	         r.add(aVal);
	      }
	   }
	   return r;
	}


	public static void main(String[] args) {
		//测试文件
		List<Map<String,Object>> data = new ArrayList<Map<String,Object>>();
		   Map<String,Object> map = new HashMap<String,Object>();
		   map.put("id",1);
		   map.put("pid",0);
		   map.put("name","甘肃省");
		   data.add(map);
		   Map<String,Object> map2 = new HashMap<String,Object>();
		   map2.put("id",2);
		   map2.put("pid",1);
		   map2.put("name","天水市");
		   data.add(map2);
		   Map<String,Object> map3 = new HashMap<String,Object>();
		   map3.put("id",3);
		   map3.put("pid",2);
		   map3.put("name","秦州区");
		   data.add(map3);
		   Map<String,Object> map4 = new HashMap<String,Object>();
		   map4.put("id",4);
		   map4.put("pid",0);
		   map4.put("name","北京市");
		   data.add(map4);
		   Map<String,Object> map5 = new HashMap<String,Object>();
		   map5.put("id",5);
		   map5.put("pid",4);
		   map5.put("name","昌平区");
		   data.add(map5);
		   Map<String,Object> map6 = new HashMap<String,Object>();
		   map6.put("id",6);
		   map6.put("pid",5);
		   map6.put("name","昌");
		   data.add(map6);
		   Map<String,Object> map7 = new HashMap<String,Object>();
		   map7.put("id",7);
		   map7.put("pid",6);
		   map7.put("name","昌");
		   data.add(map7);
		  // System.out.println(JSON.toJSONString(data));
		   JSONArray result = treeJson(JSONArray.parseArray(JSON.toJSONString(data)),"id","pid","children");
		   System.out.println(result);
	}
}
